Hello fellow Coders,
I was wondering whether const [] is more efficient than List.empty(growable: false). The latter sound more like the official way to go about it, but because I can't make it const it has to allocates a new array. Whereas the first is not only shorter but because it is const I don't see how it isn't more efficient.
Does anyone has more insight/ knows how to check the actual performance?

CodePudding user response：

const <T>[] creates a canonical, compile-time constant. The List<T> object is constructed only once.

In contrast, List<T>.empty(growable: false) has no such guarantee and can create new List<T> objects. (Arguably it could return a const List<T> object when growable is false, but then that would require a runtime check on growable, so that too would be slightly less efficient. As you've already noted, it can't do any better than const <T>[].)

CodePudding user response：

I believe the second, with List.empty actually clears the current list, without creating a reference to a new one, regardless if = [] or = const []. Interesting question though.